2011-12-07T07:30:00+01:00 Patrick Nairz 2011-12-07+01:00 https://lawine.tirol.gv.at/data/fotos/LWD_1.jpg Through the temperature rise, increasingly frequent full depth snowslides can be expected. In high alpine, particularly glacial regions, freshly formed snowdrift masses should be avoided, especially in very steep, shady terrain. The next avalanche bulletin will be published at the next heavy snowfall. Caution urged towards full depth snowslides in west, snowdrift in high alpine regions General weather conditions: Tirol is in a very powerful northwesterly air current which will bring enduring and heavy precipitation in a warm front today. Tomorrow, Thursday, weather conditions will improve again, the stormy air current slacken off somewhat. Mountain weather today: storm and snowfall, winter has returned to the mountains. Snow will be persistent out of thick fogbanks, adding up particularly quickly as the clouds lodge against the mountain barrier in the northwest, by evening bringing as much as 30 to 50 cm of fresh fallen snow. On the southern flank of the Alps, less snowfall is anticipated. Temperature at 2000 m: minus 3 degrees; at 3000 m: minus 9 degrees. Storm strength northwesterly winds. Forecast: precipitation will gradually subside, the weather turn variable. In the western parts of Tirol, winter has returned, bringing 30 - 60 cm of fresh fallen snow over the last few days. The snowfall was usually accompanied by strong northwesterly winds, facilitating snowdrift accumulation in high alpine regions. As a potential bed surface for this snowdrift, generally only the thin and small-surfaced layer of old snow from autumn is possible, predominantly found above approximately 2600 m. The bonding of this generally faceted and, thus, loosely packed layer of old snow with the fresh snowdrift is poor, even in shady terrain, where large sized ice sheets formed during the last extended period of clear, dry weather. Over the last three days there has been heavy snowfall particularly in the western parts of Tirol, namely, in Silvretta-Samnaun and Arlberg-Ausserfern, 30-60 cm. Further east, there was noticeably less new fallen snow, generally 10 cm, in East Tirol none at all. Danger zones are to be found in those western areas with the heaviest snowfall on very steep, smooth, grassy slopes, where the fresh fallen snow can be unleashed as snowslides. This type of avalanche usually signals impending release through a fissure in the snowpack, a so-called glide crack, making it relatively easy to spot. Further, above approximately 2700 m there are small avalanche prone locations in shady, very steep terrain, where from place to place fresh snowdrift has been deposited atop a thin, loosely packed old snowpack. Small slab avalanches can be triggered in such places, as also in areas immediately adjacent to ridge lines, by backcountry skiers and freeriders. With ascending altitude these danger zones tend to become more prevalent. The greatest caution is currently urged in very steep, shady glacial terrain. An unusual aspect of the winter this year is that new fallen snow has been deposited on icy sheets in shady terrain. Apart from the peril of falling, small sized avalanches can also be triggered from such spots.